Charging electric furnaces under operation



June 14, 1960 G. HAAS 2,940,620

CHARGING ELECTRIC FURNACES UNDER OPERATION Filed May 29, 1958 Fig] [2 4a INVENTOR. Gu sza v Haas. BY 6 J flzfornqf United States Patent CHARGING ELECTRIC FURNACES UNDER OPERATION Filed May 29, 1958, Ser. No. 738,832

7 Claims. (Cl. 214-18) In the operation of electric crucible furnaces the charge is inserted in the crucible in which it is melted down, by the action of the secondary current produced in the induction coil. In many cases the melting process requires that material of a different kind and different quantities be put in. In furnaces which work under vacuum or with inert gas, the crucible and the discharging means are arranged in avacuum or gas-tight container which is closed after charging. In this case it is necessary that even the filling be performed when the container is closed. The present invention fulfills this requirement by means of a construction which is characterised in that the container for the crucible is attached in a vacuum or gas-tight manner to a charging container, which in turn is joined in the same manner with a storage bin containing a charging basket which is divided into a plurality of compartments each having a bottom door, and that the opening and closing of the doors is operated by a ball maneuvering means.

The invention will now be described, by way of example with reference to the accompanying drawing in which,

Figure 1 is a vertical section through the entire furnace plant,

Figure 2 is a vertical sect-ion along the line A--A of Figure 3 through the feeding means,

Figure 3 is a horizontal section through the feeding means along the line BB of Figure 2, and

Figures 4 and 5 show details of the means according to the invention.

Referring to Figure 1, the crucible 1 supporting an induction coil '2, is inserted in a furnace container 3 having a removable cover and a bottom 5. When the complete furnace is tilted in the direction of the arrow, the molten metal flows into chills (not shown) through a casting gutter 6 which is accommodated in a vacuum or gas-tight tube-shaped casing 7. A tube-shaped charging container 8 is attached to the furnace container 3 and contains a charging means 9 by means of which the crucible may be filled with material. The container 8 supports a storage bin 10 having a removable cover 11 and housing a charging basket 12, the constructional details of which are shown in Figures 2 and 3.

The basket 12 is divided into a plurality of compartments 13 each provided with hinges 14 and bottom doors "15, which are reinforced at their inner ends by members 16. If the bottom doors 15- are closed the members 16 rest on balls 17 located in bushings 18 which in turn are located in radial holes in a tube 19 which is fixed in the centre of the basket 12. The outwardly directed openings of the bushings 18 are reduced in diameter for holding the balls in position. A shaft slidably inserted in the tube 19 consists of two parts 20 and 22. The upper end of the shaft 20 is provided with one half of a clutch means 21 which is adapted to join the shaft '20 with the other clutch half mounted on the upper shaft 22. Below the clutch 21 the shaft 20 comprises a stop member 23 adapted to engage the upper end of the tube 19. At its lower end the shaft 20 comprises a recess 24, which is provided to partly receive only one ball 17, a ring slot 25 and a stop member 26.

The shaft 22, which supports the other half of the clutch means 21 at its lower end, is journalled in a bearing 27 attached to the cover 11. At its upper end the shaft 22 supports a ball handle 28 and the bearing 29 for a lever 3%, the outer end of which is formed as a bearing 31 for a spring-operated bolt 32. The bolt 32 can lock the lever 30, and consequently the shafts 20 and 22, in difierent positions with respect to a setting disc 33 which is fixed to the bearing 27. Around its periphery the setting disc 33 has a number of setting holes 34 corresponding to the number of compartments 13. The lever 30 is provided with an extension 35 at the lower part of the bearing 31 which is used, if one of the doors 15 is opened, to engage one of a number of recesses 36 in the periphery of an adjustment disc 37 fixed to the bearing 27. The number of the recesses 36 corresponds to the number of doors 15. Between the adjustment disc 37 and the lever 30, a locking means 38 is displaceably arranged horizontally on the adjustment disc 37. The locking means 38 consists of a disc having two coherent openings with different diameters, one of which corresponds to the diameter of the lower end of the shaft 22 and the other to the reduced diameter of the upper end thereof. By rotating and hoisting the shafts 20 and 22 one bottom door 15 will be opened or all the bottom doors may be opened or closed simultaneously.

The mode of operation is as follows:

The basket 12 is inserted in the storage bin 10. Each compartment of the basket 12 containing the material to be charged into the furnace under operation, is suitably marked on the maneuvering means for the charging means, by a numeral or the like. The cover 11 is closed and the shafts 20 and 22 are coupled with each other. If for instance the compartment III is to be emptied the bolt 32 is lifted and the lever 30 is rotated until the bolt 32 stands above the setting hole III, so that the bolt can fall down into the hole. The extension 35 prevents the shaft from being lifted Whilst the lever 30 is rotated or the lever from being rotated whilst the shaft is lifted, which would have the result of an undesired compartment being opened. This rotation of lever 30 brings the recess '24 in the shaft 20 into a position' in which it is located in alignment with and below the ball 17 associated with the door 15 of compartment Hi. When the bolt 32 rests in the hole 34 corresponding to the compartment III the handle 28 is lifted a distance defined by the locking means 38 if it is in the position shown in Figure 4.

This lifts the recess 24 in the shaft 20 so that it lies in front of the ball 17 associated with the door 15 of compartment HI and enables this ball to move partly into the recess 24. The member 16 is therefore no longer supported by the ball. The door 15 of compartment III therefore opens and the material in the compartment falls on to a shaking trough 39 which shifts it into the crucible. For the purpose of supervision, inspection windows 40 may be provided at several places. In Figure l, the numeral 41 designates a hopper.

If all the compartments 13 are to be emptied practically simultaneously the locking means 38 is pushed into the position shown in dotted lines in Figure 4, so that the part of the shaft 22 of greater diameter may pass through the greater opening of the locking means. At the same time the extension 35 is moved directly below a recess 36 in the setting disc 37. The shaft 20 may then be raised to such an extent that the ring slot 25 will be level with the balls 17 in the tube 19. As the shaft is raised, one ball 17 will first move into the recess 24 and the corresponding door opens, and with a continuing upward movement of the shaft the said ball 17 is pushed outwardly and immediately thereafter the balls 17 are all in line with the ring slot 25. All the balls can then move inwards thereby releasing the members 16 below all the compartments, so that the remaining doors 15 may open almost immediately after the opening of the first door in such manner that the doors are thus opened practically simultaneously.

In this position of the shaft the bottom doors may be closed for further charging whereafter the shaft 20 is pushed down until the stop member 23 engages the upper end of the tube 19.

.4 sponds to the number of bottom doors, and a liftable and rotatable shaft in said tube having a recess for receiving only one ball and a ring slot for receiving all the balls.

2. Arrangement according to claim 1, characterised in that a yieldable ring is inserted in the ring slot.

3. Arrangement according to claim 1, characterised in that the shaft is adapted to be coupled with a second shaft which is journalled in the cover of the storage bin The ring slot 25 in the shaft 23 may be surrounded by a rubber ring 42 or the like so that the seating of the balls in the slot is yieldable (see Figure 5). In this way the closing of the doors is facilitated. When the filling is accomplished the cover 11 is opened and the chargand is provided with shafts, which means is arrestable at positions corresponding to the compartments.

4. A-rrangementaccording to claim 3, characterised in that the maneuvering means consists of a lever which is journalled on the second shaft and the outer end of which is formed as a bearing for a spring-operated bolt adapted to be pushed into any one of a number of holes which correspond to the number of compartments and which are arranged in a setting disc mounted on the cover.

ing basket 12 is removed from the storage bin 10 for further filling. Obviously the furnace plant has to be evacuated or filled with inert gas.

The structural details of the above described furnace plant may of course be modified within the scope of the ensuing claims.

What I claim is:

1. Arrangement for charging an electric furnace under operation, which is evacuated or filled with inert gas, and in which the crucible is surrounded by a vacuum or gastight container, characterised in that the container for the crucible is attached in a vacuum or gas-tight manner to a charging container, which in turn is joined in the same manner with a storage bin containing a charging basket which is divided into a plurality of compartments each having a bottom door and that the opening and closing of the doors is operated by a ball maneuvering means adapted for opening the doors in both an arbitrary sequence and practically simultaneously, the ball maneuvering means comprising a guiding tube inserted centrally into the charging basket and supporting a crown of radially movable balls, the number of which corre- 5. Arrangement according to claim 4, characterised by an adjustment disc having at its periphery a number of recesses corresponding to the number of compartments, and by an extension of the lever adapted to engage any one of the recesses for the purpose of preventing the shafts from being lifted during rotation.

References Cited in the file of this patent UNITED STATES PATENTS Newcomb et al. Feb. 7, 1956 FOREIGN PATENTS Austria Nov. 25, 1 955 

